邻苯二甲醚合成研究进展

Research Progress on the Synthesis of o-Dimethoxybenzene

邻苯二甲醚在医药、农药和化工合成领域有着广泛的应用,其主要的合成方法有邻氨基苯甲醚法、愈创木酚法、邻苯二酚法。邻氨基苯甲醚法、愈创木酚法缺点较为明显,限制了其应用。邻苯二酚法以其操作简便、原料易得、反应条件温和和环境友好性,成为工业上合成邻苯二甲醚的理想选择。根据甲基化试剂不同,邻苯二酚法制备邻苯二甲醚有以下几种:氯甲烷作为甲基化试剂时,收率高,但反应条件控制要求较高,且产物分离过程复杂;硫酸二甲酯作为反应活性高的甲基化试剂,适合于批量生产,但原料有剧毒,工艺会产生硫酸,对设备和操作人员有腐蚀性,并产生大量废水,污染环境;碳酸二甲酯作为绿色甲基化试剂时,无需碱,过程环保无害,但催化剂的选择至关重要;甲醇作为甲基化试剂时,成本低、后处理简单,但反应活性低,需选择合适的催化剂来提高邻苯二甲醚的选择性。

o-dimethoxybenzene is widely used in medicine,pesticides and chemical synthesis.Its main synthesis methods include o-aminoanisole method,guaiacol method and catechol method.The o-aminoanisole method and guaiacol method have obvious disadvantages,which limit their application.The catechol method is an ideal choice for industrial synthesis of o-phenylenediol due to its simple operation,easy availability of raw materials,mild reaction conditions and environmental friendliness.According to the different methylating agents,there are several methods for preparing o-dimethoxybenzene by catechol method.When methyl chloride is used as a methylating agent,the yield is high,but the control requirements of reaction conditions are high,and the product separation process is complicated.Dimethyl sulfate is a methylating agent with high reaction activity,which is suitable for batch production,but the raw materials are highly toxic,and the process will produce sulfuric acid,which is corrosive to equipment and operators,and a large amount of wastewater is produced,polluting the environment.When dimethyl carbonate is used as a green methylating agent,no alkali is required,and the process is environmentally friendly,but the choice of catalyst is crucial.When methanol is used as a methylating agent,the cost is low and the post-processing is simple,but the reaction activity is low,and a suitable catalyst needs to be selected to improve the selectivity of o-dimethoxybenzene.